Gmail is gearing up to block JavaScript file attachments with effect from February 13. Millions of Gmail users will not be able to send ‘.js’ files as attachments after this date. As per the company’s announcement on its G Suite Updates blog, JavaScript files (.js) are increasingly being used to spread malware. 
As per the company’s blog post-
“Gmail currently restricts certain file attachments (e.g. .exe, .msc, and .bat) for security reasons, and starting on February 13, 2017, we will not allow .js file attachments as well. Similar to other restricted file attachments, you will not be able to attach a .js file and an in-product warning will appear…,”
As you know, JavaScript files can easily run as executables. Hence, hackers will be able to easily exploit the loophole and sneak into the system. Due to this, Google has decided to block JavaScript file attachments is attributed to security reasons. Whenever you try to send any ‘.js’ file, Gmail will display a warning with the specific explanation. It will work similar to that of the other restricted file attachments.
Gmail currently restricts other file formats including .ade, .adp, .bat, .chm, .cmd, .com, .cpl, .exe, .hta, .ins, .isp, .jar, .jse, .lib, .lnk, .mde, .msc, .msp, .mst, .pif, .scr, .sct, .shb, .sys, .vb, .vbe, .vbs, .vxd, .wsc, .wsf and .wsh.
If you really need to share JavaScript files, you can use Google Drive, Google Cloud Storage. You can also opt any other third-party storage solutions. But if you will try Gmail for sending .js files you will be receiving a bounce message explaining, why the mail was blocked and was not sent.
